Elaphe Schrenckii) in Two Mountain Valleys of South Korea

Asian Herpetological Research 2011, 2(4): 223–229 DOI: 10.3724/SP.J.1245.2011.00223 Spatial Ecology of Translocated and Resident Amur Ratsnakes (Elaphe schrenckii) in Two Mountain Valleys of South Korea Jung-Hyun LEE1, 3 and Daesik PARK2* 1 Department of Biology, Kangwon National University, Chuncheon, Kangwon 200-701, South Korea 2 Division of Science Education, Kangwon National University, Chuncheon, Kangwon 200-701, South Korea 3 Present address: Department of Environmental Resources Research, National Institute of Environmental Research, Seo-Gu, Incheon 404-708, South Korea Abstract The translocation of snakes has been viewed as a useful tool to augment declining populations and to mitigate human-wildlife conflicts, even though released snakes often exhibit relatively high mortality. We radio-tracked 13 Amur Ratsnakes (Elaphe schrenckii) in the Woraksan National Park in South Korea from July 2008 to May 2009. Two of these snakes were residents, and 11 had been illegally captured in areas remote from the study site and were donated by the park office. During the study period, six of the translocated snakes were lost: two were killed by predators, one died of unknown causes, and the radio signals of three of the snakes were lost. In the field, the ratsnakes laid eggs in early August, moved into hibernacula in late November, and moved away from the hibernacula in mid-April. Compared to the resident snakes, five of the translocated snakes traveled approximately 1.3 times farther per week, and the home ranges of the translocated snakes were three to six times larger than those of the resident snakes. In addition, the translocated snakes were found underground more frequently than the resident snakes. The management recommendations resulting from this study will guide biologists and land use managers in making appropriate decisions regarding release sites and the use of gravid females in the translocation of this endangered ratsnake. Keywords Amur Ratsnake, conservation, Elaphe schrenckii, radiotelemetry, translocation 1. Introduction recent review of reptile translocations, several snake, lizard, and turtle species in North America, Europe, and Reptile populations are declining worldwide, and Australasia have been translocated (Germano and Bishop, reintroduction, supplementation and translocation 2008). However, no studies on the translocation of Asian techniques are currently being applied to encourage snake snakes have been published to date. populations to recover (Fischer and Lindenmayer, 2000; The Amur Ratsnake (Elaphe schrenckii) is the largest Armstrong and Seddon, 2008; Mullin and Seigel, 2009; snake in Korea. It is found in Russia, from Siberia to Reading et al., 2010). Translocation has been viewed as a Manchuria, Northeastern China, and most of North and useful tool for supplying snakes to declining populations South Korea (Kang and Yoon, 1975; Schulz, 1996). and mitigating human-wildlife conflicts (Reinert, 1991; Several taxonomic studies (Zhou, 2005; Woo et al., Brown et al., 2010). However, translocation often 2009; An et al., 2010) and basic ecological studies on its produces abnormal behavior and high mortality in the feeding, mating, and oviposition in captivity have been affected snakes (Dodd and Seigel, 1991; Fischer and conducted (Paik, 1979; Zhou and Zhou, 2004). In South Lindenmayer, 2000; Roe et al., 2010). According to a Korea, the ratsnake has traditionally been recognized as a divine animal, with the power to protect a house (Paik, 1979). However, field populations have declined * Corresponding author: Dr. Daesik PARK, from the Division of Science Education, Kangwon National University, South Korea, with to critically low levels as traditional rural towns have his research focusing on the basic and conservation ecology of Korean modernized; furthermore, stream systems have been amphibians and reptiles. E-mail: [email protected] modified by replacing rocky banks with concrete banks, Received: 20 August 2011 Accepted: 16 October 2011 reducing the snakes’ available habitat (Paik, 1979). 224 Asian Herpetological Research Vol. 2 Since 2005, the Amur Ratsnake has been classified as a from the park office. The translocated ratsnakes were Category I endangered species by the Korean Ministry caught at three different sites in the park: at Deoksan- of Environment. The endangered status of the Amur myeon, Cheongpung-myeon, and Susan-myeon, which Ratsnake indicates an urgent need for field studies aiming are 9.0 km, 16.5 km, and 15.3 km from the study site, to conserve and rehabilitate the remaining populations. respectively. Considering the average distance traveled During the planning phase of our radio-tracking study and the home range size of other ratsnakes (Durner and of the Amur Ratsnakes in the Woraksan National Park Gates, 1993; Sperry and Taylor, 2008), it is unlikely that in July 2008, we were given 11 (five females and six any of these ratsnakes were native to the study site. The males) adult Amur Ratsnakes by the park office. A local surviving ratsnakes were collected at the end of the study policeman and park rangers found the snakes, which had and are now being used in the captive breeding program been illegally collected in areas remote from the study for the Amur Ratsnakes that is conducted at the Chiaksan site between April and July 2008 and kept in a private National Park. Before implanting the transmitters for residence. Hereafter, we will refer to these 11 ratsnakes radio-tracking, we measured the snout-vent length (SVL) as the “translocated snakes”. The goal of this study was of each ratsnake to ± 0.1 cm and weighted the snake to ± to investigate the basic spatial ecology of resident and 0.1 g with a field balance (ELT4001, Sartorius, NY, USA). translocated Amur Ratsnakes in mountain valleys in the For individual identification, we used a needle to insert a Woraksan National Park using radiotelemetry. The results passive, integrated transponder tag (TX1411L, Biomark, could be used to design translocation projects for this Boise, ID, USA) under the dorsal skin of each ratsnake. endangered ratsnake in the future. We surgically implanted an SI-2 transmitter (18 g; Holohil Systems Ltd., Carp, Ontario, Canada) into the 2. Materials and Methods abdominal cavity of each ratsnake (Lee et al., 2011). The weight of the transmitter averaged 2.7% (ranging between 2.1 Study area We conducted our study in two 2.0% – 3.1%) of the body weight of the snake. Following neighboring small mountain valleys, the Golmoe and the implantation, the ratsnakes were individually allowed Guraegol valleys, which are approximately 2.5 km to recover for approximately one week in a plastic cage apart (36° 52’ N, 128° 04’ E) in the Woraksan National (60 cm long × 40 cm wide × 17 cm high) (Lee et al., 2 Park. The park occupies an area of 288 km in three 2011). The ratsnakes were released once they had been administrative districts in the central region of the Korean recovered from the surgery. Peninsula (Jecheon-si, Moonkyeong-si, and Danyang- Because we speculated that the areas where we caught gun), and it includes more than five mountains that are the resident ratsnakes could be appropriate translocation over 1000 m above sea level. The mountains surrounding sites, we released each resident snake along with several the study valleys are generally covered by deciduous translocated snakes in each valley. A female resident woodlands, and have many rock cliffs and rocky outcrops. snake, No. 590, was released with five translocated The dominant trees in the mountains are Mongolian oak snakes, two females (No. 830 and No. 900) and three (Quercus mongolica), Oriental cork oak (Q. variabilis), males (No. 890, No. 531, and No. 810), at the mouth and Korean red pine (Pinus densiflora), and the dominant (three snakes) and in the middle (three snakes) of the shrubs are Japanese spicebush (Lindera obtusiloba), Golmoe Valley, where No. 590 was caught. Another fragrant snowbell (Styrax obassia), and Korean rosebay female resident snake, No. 782, was released in the (Rhododendron mucronulatum), listed in order of their middle of the Guraegol Valley, where she was caught, relative abundance. The mountain habitats are bordered with six translocated snakes, three females (No. 390, No. by small areas of grassland, crop fields with rock fences, 970, and No. 991) and three males (No. 270, No. 510, and and stream banks; a paved road follows the mountain No. 760). We tried to maintain a 1:1 ratio of males and streams in the valleys of the study site. In some locations, females released into each area. After release, we began the stream bank is immediately adjacent to the roadside. the radio-tracking of these ratsnakes. 2.2 Radiotelemetry We conducted radiotelemetry To follow the transmitter signals, we used a TR-1000 between 14 July, 2008, and 15 May, 2009. We captured receiver combined with a three-element Yagi antenna two female resident ratsnakes with a snake-stick in (Wildlife Materials Inc., Murphysboro, IL, USA). We the Golmoe and Guraegol valleys in the National radio-tracked the ratsnakes weekly between 14 July Park during the first week of July, and received 11 and 9 December, 2008; monthly, between January and additional adult ratsnakes (five females and six males) March 2009; and resumed weekly tracking between 3 No. 4 Jung-Hyun LEE et al. Radio-tracking of Translocated Ratsnakes 225 April and 5 or 10 May, 2009. The last two radiotelemetry animal movement extension for ArcView GIS. For the sessions were conducted to determine whether the snakes kernel method, we obtained fixed 50% and 95% estimates had survived the hibernation period. When we detected by applying the least squares cross-validation criterion a snake’s signal, we determined the coordinates of its to choose the smoothing parameters (Row and Blouin- location using a hand-held GPS unit (Vista CX, Garmin, Demers, 2006; Lee et al., 2011). The size of the home New Taipei, Taiwan, China) and described the structural range was defined as the area that the ratsnake used features of the site (See below).

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